The crystal and molecular structure of the narcotic antagonist Naltrexone will be completed. All 56 non-hydrogen atoms corresponding to 2(C22H23NO4-Hcl) have been located in the unit cell. In addition, six water molecules of hydration have been located, although there is some evidence of disorder. By taking into account the possible disorder, it should be possible to improve the refinement to the point where a difference Fourier will reveal the hydrogen atoms. It will then be possible to elucidate the hydrogen bonding system and compare Naltrexone with other opiates.